Mobilised and on their way to the border – along with full-time soldiers, Israel’s cabinet has given the military the go-ahead to call up 75,000 reservists for a possible Gaza invasion.

The move comes after Palestinian militants fired a rocket towards Jerusalem for the first time in decades.

Tel Aviv has also come under rocket fire in defiance of an Israeli air offensive aimed at stopping the militant rocket attacks.

Over night there were further Israeli air strikes on Gaza City. A compound belonging to Hamas, the Islamist group which runs the Gaza Strip, was hit.

Israel has blocked access to three major routes leading into Gaza declaring it a “military zone”, increasing speculation that a ground attack is imminent.

Since Wednesday when Israel killed Hamas’s military chief, officials say at least 29 Palestinians have died including several children. Three Israelis were killed in a rocket attack on Thursday.

US President Barack Obama has spoken with both Egypts’s President Mohamed Morsi commending his efforts to start negotiating a truce while discussing ways of de-escalating the situation with Israel’s Prime Minister Benjamin Netanyahu.